1. Field of the Invention
The present invention relates to a fixing member used in an electrophotographic image forming apparatus such as a copying machine or a printer, and a heating apparatus and an electrophotographic image forming apparatus using the fixing member.
2. Description of the Related Art
The fixing member used in the heating apparatus of, for example, an electrophotographic image forming apparatus generally has an elastic layer including silicone rubber so as to avoid excessive crushing of toner and the like. Additionally, on the surface of the elastic layer, for the purpose of suppressing the adhesion of the toner and the like, a surface layer including a fluororesin is disposed. However, there is a problem such that the adhesion between the surface layer including a fluororesin and the elastic layer is low.
For the purpose of solving such a problem, Japanese Patent Application Laid-Open No. 2005-212318 proposes the inclusion of a metal oxide in an elastomer substrate and the formation of a fluororesin coating layer including a phosphate group on the substrate. Japanese Patent Application Laid-Open No. 2005-212318 also discloses that such a constitution allows the phosphate group and the metal oxide to interact with each other so as to achieve a sufficient adhesive strength between the fluororesin and the elastomer substrate. In addition, Japanese Patent Application Laid-Open No. 2005-212318 also proposes a further formation of a fluororesin layer through the intermediary of the fluororesin coating layer so as to form a laminate, and discloses that in such a constitution, the fluororesin coating layer and the fluororesin layer have affinity to each other, and hence the fluororesin coating layer functions as the primer for the fluororesin layer.
On the basis of the disclosure of Japanese Patent Application Laid-Open No. 2005-212318, the present inventors have investigated a fixing member that uses the fluororesin coating layer having a phosphate group as a primer in the formation of the fluororesin layer on a silicone rubber layer including alumina as a metal oxide. Consequently, when the fixing member was used for thermal fixing of electrophotographic images over a long term, the interfacial peeling between the surface layer including the fluororesin and the elastic layer including the silicone rubber sometimes occurred. In other words, it has been found that there is still room for improving the adhesion durability between the surface layer and the silicone rubber.